Method of operating a multiphase transformer having the windings for one phase inoperative.



NO. 821,521. PATENTED MAY 22, 1906.

W. s. MOODY. METHOD OF OPERATING A MULTIPHASE TRANSFORMER HAVING THE WINDINGS FOR ONE PHASE INOPERATIVE.

APPLICATION FILED OCT. 22, 1904.

Fig. I. Fig. 2.

W'tnesses: Q Inventor: M M \ffilaawl'l'der" smeo'dg,

rinrrn srarns NAIJIER S. MOODY, OF SUHENEOTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD OF OPERATlNG A MULTIPHASE Specification of Letters Patent.

TRANSFORMER HAVKNG THE WINDINGS FOR ONE PHASE lNOPERATIVl-I.

. Patented ma 22, ieoe.

Application filed October 22.190d. Serial No. 229,577-

Windings for One Phase'Inoperative, of

which the following is aspecification.

It has frequently been urged against the use of a multiphase transformer with inter-.

linked magnetic circuits that if one or more windings become damaged by short-circuiting, grounding, or through any other defect it is, impossible to operate from the undamaged windin s of the other phasesflzs would be the case it a single-phase transformer were used in each phase of the multiple-phase systerm. I have discovered, however, that this objection is not as important as it seems, but that for many purposes'such a transformer of the shell type may be employed exactly as could the remaining undamaged single-phase transformers.

Where the windings of one or more of the hases of a multiple-phase shell-type transormer having interlinked magnetic circuits become inoperative for any reason, I shortcircuit the high-potential winding of the damaged phase of the transformer upon itself. Similarly, I shortcircuit the corresponding low-potential winding ofv the transformer upon itself. The windings thus short-sin cuited will choke down the flux passing through the portion of the core surrounded by them without generating in any portion of the windings a current greater than a small fraction of the full-load current in such por tion.

In some cases, as of serious short-circuiting or the like, it may be that one or more open circuits are produced in the damaged windings. In that case I separate the windings and short-circuit enough portions of the windin s to prevent the passage of an appreciable i ux through them without the generation of large enough currents in said portions to produce dangerous heat effects. After the damaged windings are short-circuited in the manner described the perfect windings for the other phases can be put in service andv used exactly as could a similar number of single-phase transformers. Itwill of course be understood that where, for instance, the winding ofone phase ota three-phase trans former is damaged the two remaining phases will safely carry only two-thirds of the normal full load of the transformer. This would also be the case, however, if one of three singlee-phase transformers used in a three-phase system were damaged.

The various features of novelty which ch acterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of my invention, however, reference may be had to the accompanying drawings, of which- 1 in section of a three-phase shell-type trans-- former with interlinked magnetic circuits. Fig. 2 is a diagram of the windings of the transformer in its normal condition. Fig. 3 is a diagram showing the connections with one phase inoperative, and Fig. I shows an arrangement where the winding for one phase is injured in a manncrdifierent from that shown in Fig. 3.

In the drawings, 1 represents the core of the transformer, and 2, 3, and 4 represent the high-potential windings for the different phases of the transformer, while 2, 3, and 4 represent the low-potential windings of the transformer. While in the drawings I have shown. the high and low potential windings of each phase in sections passing side by side through apertures formed for the purpose in the core, it will of course be understood. that in the actual transformer the high and low potential portions of the windings of each phase are ordinarily subdivided and inter meshed.

In the normal 0 I eration of the transicvn the highotentia windings 2, 3, and 4 connecte 'in delta, as shown, to the .l potential main conductors 5, 6, and 7, shown in Fig. 2. Similarly, the windings 2., 3, and 4 are connected to the low-potential. main conductors 5, 6, and 7 V'Vl'ien the transforn'ier becomes delective--- as, for instance, by the short-circuitin o portion of the turns of the low-po winding",- as indicated at 8 in Fig. 3 connect the winding 4 from the windm and 3 and from the conductors 5 and nd then connect the terminals of the windin Figure l is a plan view with the windings i v v I til , winding 4 of the phase, as above described.

The short-circuited windings 4 and 4 prevent the passage of any but a very small flux through the portion of the core surrounding them, and the current induced in no portion of the windings 4 and 4- will be larger than a small fraction of the normal full-load current of the windings at and 4. The windings 2 and 2 and 3 and 3 can then be used exactly as could two single-phase transformers in a three-phase system.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The method of operating a three-phase shell-type transformer, which consists in delta-connecting the windings for two of the phases into a three-phase system, and shortcircuiting part or all of the windings of the other phases.

2. The method of operating a multiphase shell-type transformer, which consists in connecting the windings for some of the phases in a multiphase system and closing the remaining windings upon themselves.

3. The method of operating a multiphase shell-type transformer having a number of core portions normally surrounded by windings, each of said windings being normallv connected into a multiphase system which consists in replacing one or more of said windings with windings short-circuited upon themselves.

4. The method of operating in a multiphase system, a multiphase shell-type transformer-having as many core-sections as there are branches in the multiphase system, which consists in connecting windings surrounding some of said core-sections into the multiphase system, and roviding means for practically eliminating tie passage of magnetic fluxes through the remaining of said core-sections.

5. The method of operating in a multiphase system, a multiphase shell-type transformer having as many circuits of magnetic material as there are branches in amultiphase system, which consists in connecting windings placed about certain of said circuits in a multiphase system, and short-circuiting windings placed about the remaining of said circuits.

6. The method of operating a multiphase l transformer having a pluralit of core-seci tions arranged and connecte together so that a plurality of closed magnetic circuits 5 are formed which include some of said sections but do not include one of said sections, which consists in practically eliminating the passigeof magnetic fluxes through said one of said sections, and connecting windings surrounding others of said sections into a multiphase system.

7 The method of operating a multiphase transformer having a. core comprising portions each of which normally forms a art of the paths for multiphase fluxes, whic consists in practically eliminating the flux through one of said portions, While allowing multiphase fluxes to pass through others of said portions.

In witness whereof I have hereunto set my hand this 21st day of October, 1904.

WALTER S. MOODY.

Witnesses BENJAMIN B. HULL,

' HELEN ORFORD. 

